I don't know who Toby is specifically in this story without reading it. He could be a child, a little animal, or even an adult with a child - like sense of wonder during Christmas.
Since the title only gives us the name Toby in relation to a Christmas story, he could be a variety of things. He could be a kind - hearted person who spreads Christmas cheer around his town. Maybe he's a lonely soul who finds warmth and friendship during Christmas. He could also be a naughty character who has a change of heart during the holidays.
Toby could be anyone. Maybe it's a friend of the speaker, someone in a writing group, or just a fictional name used to make a general point about writing novels. Without more context, it's hard to say exactly who Toby is.
There could be a psychic character. This person might be able to sense things that Toby can't and help him understand the nature of the paranormal activities. Another character could be Toby's best friend who is skeptical at first but then gets drawn into the strange events.
Naruto could be one of his allies. Naruto has this knack for seeing the good in people and would probably be willing to give Obito a chance to redeem himself. Also, Sakura, with her skills as a medic - ninja, could be an ally. She might help heal Obito if he was injured during the war and see the potential in him to be a force for good.
There could also be interactions with the new generation of ninjas. They might view Obito as a sort of legend or a cautionary tale. Their fresh perspectives could either inspire Obito to change further or make him feel even more out of place in this new post - war ninja world.
Well, the reborn character could explore Obito's Sharingan powers in new ways. Instead of using them mainly for combat like Obito did in the original story, they could focus on using the Sharingan to understand the emotions of others. For example, they could use it to detect lies and hidden motives, which would be a unique twist on the power.
Besides Obito, Sasuke could be a main character in this fanfiction. Sasuke, with his own journey of redemption and his understanding of power and the ninja world, could have an interesting dynamic with the reincarnated Obito. Also, Sakura might play a role. She could be the one who tries to heal the reincarnated Obito, both physically if he is injured during his new adventures and emotionally from the traumas of his past life.
Often, Obito is attracted to Kushina's strength and kindness. He might try to impress her with his own abilities. Their interactions could involve Obito being a bit clumsy in his attempts at first. Kushina, on the other hand, might find his eagerness endearing and start to open up to him more. They could share stories about their pasts, their dreams, which deepens their bond.